The LEDs I chose are made by Pilot, size 194. These are incredibly thin, and fit inside this very confined space perfectly. Removing the clear lenses from the housings is by far the biggest challenge. Using a small flat screwdriver, gently, but firmly pry the lens from the housing. It is almost guaranteed it will not come off in one clean piece. These are not designed to ever be taken apart. Expect some cracking, and small bits of the plastic housing to remain attached to the clear lens.